This section is intended to introduce various aspects of the art, which may be associated with exemplary embodiments of the present techniques. This discussion is believed to assist in providing a framework to facilitate a better understanding of particular aspects of the present techniques. Accordingly, it should be understood that this section should be read in this light, and not necessarily as admissions of prior art.
Hydrocarbon reserves are becoming increasingly difficult to locate and access. Typically, various methods are utilized to collect measurement data and then to predict the location of potential hydrocarbon accumulations. For example, reflection seismology is the dominant technique for identifying the location of potential hydrocarbon accumulations. This technique is used to identify structures that may hold hydrocarbon accumulations and may also be utilized to image the hydrocarbon fluids within subsurface accumulations as direct hydrocarbon indicators (DHIs). However, seismic imaging may be challenging in cases where the acoustic impedance contrasts that generate DHIs are great diminished or absent, for example, in the imaging of subsurface geological features at increasing depth, sub-volcanic features, or sub-salt features. Consequently, seismic imaging technology may lack the required fidelity to provide accurate assessments of the location, volume, and fluid composition of subsurface hydrocarbon accumulations.
Similarly, non-seismic hydrocarbon detection technologies, such as potential field based methods, like gravity or magnetics, may lack the fidelity to identify hydrocarbon accumulations. Other non-seismic hydrocarbon accumulation detection technologies, such as geological extrapolations of structural or stratigraphic trends, may provide exploration prospects, but cannot directly detect hydrocarbon accumulations.
Hydrocarbon seepage at the sea floor or on land may provide some indication of an active or working hydrocarbon system where hydrocarbons have been generated and expulsed. However, hydrocarbons may also be produced from microbial degradation of organic matter in the subsurface that may or may not be associated with an accumulation or reservoir. Thus, it can be difficult to determine whether such hydrocarbon seepages migrated directly from a source rock, from a failed trap without significant residence time within an accumulation, or from an existing hydrocarbon accumulation.
Sequencing of nucleic acids found in field samples may provide information that can be helpful for determining the general source of hydrocarbons in seeps. For example, microorganisms present may be associated with the consumption of subsurface biologic material, forming hydrocarbons, or with the consumption of hydrocarbons released from a reservoir as an energy source. The identification of the microorganisms present may be performed by an analysis of the nucleic acids present in the sample. However, nucleic acids can be difficult to isolate and extract from field samples, such as subsea samples and/or samples containing hydrocarbons.
As a result, there remains a need for enhanced techniques for the isolation and extraction of nucleic acids from field samples. Such enhanced techniques may allow for more effective sequencing of the nucleic acids from, for example, microorganisms, and thus, a more effective determination of the type of hydrocarbons present in a seep.
Background references may include PCT Publication Nos. WO 2010/109173 A1, WO 2013/119350 A1, WO 2015/103165 A1, and WO 2015/103332 A2; US Patent Application Publication Nos. US 2006/0154306 A1, US 2010/0279290 A1, US 2014/0051847 A1, and US 2015/0185126 A1; U.S. Pat. Nos. 6,852,495 B2, 7,459,548 B2, 8,877,918 B2, 9,145,553 B2, 9,416,356, 9,528,105, and 9,540,636; and Chinese Patent Application Publication Nos. CN 101864488 A, CN 102732504 A, CN 103667255 A, CN 104630204 A, and CN 104651350 A.